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    <title>Document</title>
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    <script>
        function sky() {
            // (1)正常的声明多个变量
            var a = 9,
                b = 9,
                c = 9;
            // （2）下面代码声明的则是a是当前局部变量，b和c都是全局变量
            var a = b = c = 9;
            var a = 9;
            b = 9;
            c = 9;
            console.log(a);
            console.log(b);
        }
    </script>
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